Controller for optical device, exposure method and apparatus, and method for manufacturing device

ABSTRACT

An exposure method for exposing a mask pattern, which includes plural types of patterns, with a high throughput and optimal illumination conditions for each type of pattern. The method includes guiding light from a first spatial light modulator illuminated with pulse lights of illumination light to a second spatial light modulator and exposing a wafer with light from the second spatial light modulator, accompanied by: controlling a conversion state of the second spatial light modulator including a plurality of second mirror elements; and controlling a conversion state of the first spatial light modulator including a plurality of first mirror elements to control intensity distribution of the illumination light on a predetermined plane between the first spatial light modulator and the second spatial light modulator.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Japanese Patent Application No.2007-289090, filed on Nov. 6, 2007 and U.S. Provisional Application No.60/996,405, filed on Nov. 15, 2007.

BACKGROUND

The present invention relates to an exposure technique for exposing anobject with a plurality of optical elements capable of spatiallytransforming light (spatially modulating light) and to a devicemanufacturing technique using such exposure technique.

In a lithography process for manufacturing devices (electronic devicesand micro-devices), such as semiconductor devices and liquid crystaldisplay devices, an exposure apparatus such as a batch exposure typeprojection exposure apparatus, like a stepper, or a scanning exposuretype projection exposure apparatus, like a scanning stepper, is used totransfer a predetermined pattern onto a wafer (or glass plate etc.).

In an exposure apparatus of the prior art, to form different circuitpatterns in a plurality of layers on a device that is subject toprocessing, masks are exchanged for each layer to perform exposure.Further, when a circuit pattern for a single layer includes, forexample, two types of circuits patterns having different microscopiclevels, mask patterns for the two types of circuit patterns are formedon two different masks. The patterns of the two masks are sequentiallyexposed in a superimposed manner onto a wafer while optimizingillumination conditions to perform double exposure. In this manner, whenexchanging masks for each device, each layer, or each pattern type,throughput is decreased in the exposure process.

Therefore, an exposure apparatus has been proposed to use, in lieu ofmasks, two mirror devices including an array of a plurality of movablemicro-mirrors and control the direction of reflection light for eachmicro-mirror of the two mirror devices in order to produce lightintensity distribution in correspondence with a transfer pattern (forexample, refer to Japanese Laid-Open Patent Publication No. 2006-13518).In this exposure apparatus, the two mirror devices are illuminated withlinear polarized lights of which polarization directions are orthogonalto each other. Two types of patterns are simultaneously exposed bysynthesizing light beams from the two mirror devices and generatingillumination light that exposes a wafer.

SUMMARY

In the exposure apparatus of the prior art that uses mirror devices, tosubstantially expose two types of patterns during a single exposure, thetwo mirror devices must be simultaneously illuminated with illuminationlights of different polarization states. As a result, the mechanism forproducing light intensity distribution in correspondence with a maskpattern is complicated, and the structure of an illumination opticalsystem is complicated.

Further, the polarization direction of the lights from the two mirrordevices must always be orthogonal to each other. Thus, the two types ofpatterns that can be simultaneously exposed are limited to patterns thatare illuminated with illumination light of different polarizationstates.

Accordingly, it is an object of the present invention to provide anexposure technique, which increases throughput and easily optimizes theillumination conditions for each of plural types of patterns whenexposing a pattern including the plural types of patterns, and a devicemanufacturing technique using such an exposure technique.

In the present invention, an exposure method for exposing an object witha plurality of pulse lights includes guiding light from a first opticaldevice (13) illuminated by the pulse lights to a second optical device(25) and exposing (step 107) the object with light from the secondoptical device (25); accompanied by: a first step (step 104) ofcontrolling a conversion state of the second optical device (25) thatincludes a plurality of second optical elements (5); and a second step(step 106) of controlling a conversion state of the first optical device(13) that includes a plurality of first optical elements (3) to controlintensity distribution of the pulse lights on a predetermined planebetween the first optical device (13) and the second optical device(25).

In the present invention, an exposure apparatus for illuminating anirradiated plane with a plurality of pulse lights and exposing an objectwith the plurality of pulse lights from the irradiated plane includes anillumination optical system (ILS) arranged upstream of the irradiatedplane and including a first optical device (13) which includes aplurality of first optical elements (3); a second optical device (25)arranged on or near the irradiated plane and including a plurality ofsecond optical elements (5); and an illumination controller (30, 45, 31)which controls a conversion state of the first optical device (13) or aconversion state of the second optical device (25).

In the present invention, a controller for controlling a conversionstate of a first optical device (13) and a conversion state of a secondoptical device (25) includes a main control unit (30) which controls theconversion state of the first optical device (13) or the conversionstate of the second optical device (25) whenever a plurality of pulselights are emitted from a light source.

In the present invention, when exposing a mask pattern including pluraltypes of patterns, for example, the conversion state of a second opticaldevice is controlled for each of a predetermined number of pulse lightsto sequentially produce variable light intensity distributionsubstantially corresponding to the plural types of patterns, and anobject is exposed with light having such light intensity distribution.This exposes the mask pattern in a manner enabling high throughput to beobtained.

During exposure, the conversion state of the first optical device iscontrolled in accordance with the conversion state of the second opticaldevice or the pattern that is to be formed on the object (e.g., patterndata of mask pattern, mask, or exposure subject, pattern that is to beformed on then object, and pattern data) to control the distribution ofthe inclination angle of light entering the second optical device. Thiseasily optimizes the Illumination conditions for each of the pluraltypes of patterns.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram showing an exposure apparatus according toa first embodiment of the present invention;

FIG. 2(A) is an enlarged perspective view showing part of a spatiallight modulator 13 of FIG. 1;

FIG. 2(B) is an enlarged perspective view showing a drive mechanism fora mirror element 3 of FIG. 1;

FIG. 2(C) is an enlarged perspective view showing a mirror elementhaving a concave surface;

FIG. 3(A) is a diagram showing the inclination angle of the mirrorelement 3 in the spatial light modulator 13 of FIG. 1 during dipolarillumination;

FIG. 3(B) is a diagram showing a secondary light source of FIG. 3(A);

FIG. 3(C) is a diagram showing the inclination angle of the mirrorelement 3 in the spatial light modulator 13 during normal illumination;

FIG. 3(D) is a diagram showing a secondary light source of FIG. 3(C);

FIG. 3(E) is a diagram showing another dipolar secondary light source;

FIG. 3(F) is a diagram showing a secondary light source for annularillumination;

FIG. 4(A) is a diagram showing one example of a pattern on a reflectionsurface of a spatial light modulator 25 of FIG. 1;

FIG. 4(B) is an enlarged view showing portion B of FIG. 4(A);

FIG. 4(C) is a diagram showing another example of a pattern on thereflection surface of the spatial light modulator 25;

FIG. 5(A) is a diagram showing one example of a mask pattern MP;

FIG. 5(B) is a diagram showing a state in which a transferred region 26Mis moved from the state of FIG. 5(A);

FIG. 5(C) is a diagram showing a state in which the transferred region26M is moved from the state of FIG. 5(B);

FIG. 6(A) is a diagram showing a shot region of a wafer during scanningexposure;

FIG. 6(B) is a diagram shot region of a wafer during step and repeatexposure;

FIG. 7 is a flowchart showing one example of an exposure operation inthe first embodiment;

FIG. 8 is a schematic diagram showing an exposure apparatus according toa second embodiment of the present invention; and

FIG. 9 is a schematic diagram showing an exposure apparatus according toa third embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A first embodiment of the present invention will now be discussed withreference to FIGS. 1 to 7.

FIG. 1 is a schematic diagram showing an exposure apparatus 100 of thisembodiment. The exposure apparatus 100 includes an exposure light source10, an illumination optical system ILS, and a second spatial lightmodulator 25. The light source 10 emits pulse lights. The illuminationoptical system ILS illuminates an irradiated plane with exposureillumination light (exposure light) IL from the light source 10. Thesecond spatial light modulator 25 includes a two-dimensional array of aplurality of mirror elements 5, which are micro-mirrors having variableinclination angles and are arranged on or near the irradiated plane.Further, the exposure apparatus 100 includes a projection optical systemPL, a wafer stage WST, a main control system 30, and various controlsystems. The projection optical system PL receives illumination lightIL, which substantially corresponds to light from a variable patternthat is to be formed by the mirror elements 5, and projects an image ofthe pattern onto a wafer W (photosensitive substrate). The wafer stateWST positions and moves the wafer W. The main control system 30 isformed by a computer that controls the operation of the entireapparatus. In FIG. 1, the Z axis is set to be orthogonal to a guidesurface (not shown) of the wafer stage WST. In a plane orthogonal to theZ axis, the Y axis is set to be parallel to the plane of FIG. 1, and theX axis is set to be orthogonal to the plane of FIG. 1. In thisembodiment, the wafer W is scanned in the Y direction (scanningdirection) during exposure.

As the light source 10 of FIG. 1, an ArF excimer laser light source isused which emits substantially linear polarization light having awavelength of 193 nm and a pulse width of about 50 ns in pulse lights ata frequency of 4 to 6 kHz. As the light source 10, a KrF excimer laserlight source generating pulse lights having a wavelength of 248 nm, anF₂ laser light source generating pulse lights having a wavelength of 157nm, and a light-emitting diode generating pulse lights may also be used.Further, as the light source 10, a solid pulse laser light source thatgenerates high harmonic wave laser light output from a YAG laser,semiconductor laser, or the like may be used. Alternatively, a solidpulse laser light source that generates high harmonic wave laser lightby amplifying semiconductor laser light with a fiber amplifier can beused. A solid pulse laser light source, for example, emits laser lighthaving a wavelength of 193 nm (other wavelengths are also possible) anda pulse width of about 1 ns in pulse lights at a frequency of 1 to 2MHz.

In this embodiment, a power supply control unit 9 is connected to thelight source 10. The main control system 30 of the exposure apparatus100 provides the power supply control unit 9 with light emission triggerpulses TP, which is for instructing the timing and light intensity(pulse energy) of the pulse light emissions. In synchronism with thelight emission trigger pulses, the power supply control unit 9 emitspulse lights in accordance with the instructed timing and lightintensity.

The illumination light IL emitted from the light source 10 and formed bylaser pulse lights, which are substantially parallel light beams eachhaving a rectangular cross-section, enters a beam expander 11. The beamexpander 11, which includes a concave lens and a convex lens, enlargesthe cross-sectional shape of the illumination light IL to apredetermined shape. A converging lens 12 illuminates the reflectionsurfaces of a plurality of mirror elements 3, which are micro-mirrorshaving variable inclination angles and arranged in a two-dimensionalarray on an upper surface of a first spatial light modulator 13, withthe illumination light IL emitted from the beam expander 11. The spatiallight modulator 13 includes a drive unit 4, which independently controlsthe inclinations angle of the reflection surface of each mirror element3 about two perpendicular axes. The spatial light modulator 13independently controls the inclination direction and inclination angleof the reflection surface of each mirror element 3 (controls theconversion state of the spatial light modulator 13) so that theillumination light IL is reflected in any number of directions(described later in detail). Further, the spatial light modulator 13forms a desired pupil brightness distribution in a far field. Whenever apredetermined number of pulse lights (one pulse light or a plurality ofpulse lights) of the illumination light IL is emitted, the spatial lightmodulator 13 provides a modulation control unit 31 with information onillumination conditions based on information of a transfer pattern.Accordingly, the modulation control unit 31 provides the drive unit 4with setting information on the inclination direction and inclinationangle of each mirror element 3. Further, the main control system 30 mayprovide, in advance, the modulation control unit 31 with the informationon illumination conditions based on the information on the transferpattern, and the modulation control unit 31 may provide the drive unit 4with the setting information on the inclination direction andinclination angle of each mirror element 3 in accordance with the pulselight emissions of the illumination light IL. In such a case, the maincontrol system 30 may provide the modulation control unit 31 with thelight emission trigger pulses TP.

A polarization optical system (not shown), which combines, for example,a half wavelength plate for changing the polarization direction of theillumination light IL, a quarter wavelength plate for converting theillumination light into circular polarized light, and a wedge-typedouble refraction prism (a wedge-type birefringent prism) for convertingpredetermined linear light into random polarized light (unpolarizedlight) may be arranged between the beam expander 11 and the converginglens 12. By using such a polarization optical system, the polarizationstate of the illumination light IL irradiating the wafer W may becontrolled to obtain linear polarization, in which the polarizationdirection is the X direction or the Y direction, circular polarization,or unpolarization so as to perform the so-called polarizationillumination.

The reflection surfaces of the spatial light modulator 13 (reflectionsurfaces of the plurality of mirror elements 3), a relay optical system14, and a fly's eye lens 15 (optical integrator) are arranged along theoptical axis AXI of the illumination optical system ILS. Theillumination light IL reflected by each mirror element 3 of the spatiallight modulator 13 enters the fly's eye lens 15 via the relay opticalsystem 14. The reflection surface of each mirror element 3 issubstantially arranged on a front focal plane of the relay opticalsystem 14, and the incident surface of the fly's eye lens 15 issubstantially arranged on the rear focal plane of the relay opticalsystem 14. However, this layout is not limited in any manner. The relayoptical system 14 functions to converge the illumination light ILreflected by each mirror element 3 onto a predetermined range about aposition on the fly's eye lens 15 in the X direction and the Z directiondetermined in accordance with the angle of the illumination light ILrelative to the optical axis AXI.

In other words, the illumination light IL entering the spatial lightmodulator 13 is divided and provided for each mirror element 3 and thenselectively deflected (reflected) in a predetermined direction andpredetermined angle in accordance with the inclination direction andinclination angle of each mirror element 3. Then, the reflection lightfrom each mirror element 3 enters the incidence surface of the fly's eyelens 15 from a position that is in accordance with the direction andangle.

The illumination light IL entering the fly's eye lens 15 istwo-dimensionally divided by a plurality of lens elements to form alight source on the rear focal plane of each lens element. This forms ona pupil plane (illumination pupil plane 22) of the illumination opticalsystem IL, or the rear focal plane of the fly's eye lens 15, a secondarylight source having substantially the same light intensity distributionas the illumination region formed by the light beams entering the fly'seye lens 15. That is, a secondary light source is formed bysubstantially planar light sources. In this embodiment, the inclinationdirection and inclination angle of the reflection surface of each mirrorelement 3 in the spatial light modulator 13 is independently controlledto control the light intensity distribution on the incident surface ofthe fly's eye lens 15 and ultimately, the light intensity distributionof the secondary light source on the illumination pupil plane 22 at anydistribution. A micro-lens array or the like may be used in lieu of thefly's eye lens 15.

In this embodiment, the second spatial light modulator 25, which isarranged on the irradiated plane or a plane near the irradiated plane,undergoes Köhler illumination. Thus, the plane on which theabove-described secondary light source is formed is conjugated with anaperture stop (not shown) of the projection optical system PL and may beconsidered as the illumination pupil plane 22 of the illuminationoptical system ILS. Typically, the irradiated plane (the plane on whichthe second spatial light modulator 25 is arranged or the plane of whichthe wafer W is arranged) for the illumination pupil plane 22 serves asan optical Fourier transform plane. The brightness distribution refersto brightness distribution (pupil brightness distribution) on theillumination pupil plane 22 of the illumination optical system ILS or aplane conjugated with the illumination pupil plane 22. However, when thefly's eye lens 15 has a large number of divided wavefronts, the mainbrightness distribution on the incident surface of the fly's eye lens 15is highly interrelated with the main brightness distribution on theentire secondary light source (pupil brightness distribution). Thus, thebrightness distribution on the incident surface of the fly's eye lens 15and on a plane conjugated with the incident surface may be considered asthe pupil brightness distribution.

One example of a spatial light modulator carries out spatial modulationon predetermined light. In this embodiment, the conversion state of thespatial light modulator is a state in which the entrance or exit oflight into or out of the spatial light modulator changes the amplitude,transmittance, phase, and in-plane distribution of the light. Forexample, in a reflective type spatial light modulator, a conversionstate of the spatial light modulator refers to a change in theinclination direction and inclination angle of each mirror element or achange in the distribution of the inclination direction and inclinationangle of each mirror element. The conversion state may also refer to,for example, the supplying and cutting of drive power to each mirrorelement, as will be described later or the distribution of the supplyingand cutting. Further, as will be described later, the spatial lightmodulator includes a phase type spatial light modulator and atransmissive type spatial light modulator.

In FIG. 1, the illumination light IL, which is from the secondary lightsource and formed on the illumination pupil plane 22, travels through afirst relay lens 16, field stop 17, an optical path deflection mirror18, a second relay lens 19, and a condenser optical system 20 toward amirror 21, which deflects the optical path toward the irradiated plane(designed plane on which a transfer pattern is arranged). Theillumination light IL reflected diagonally upward by the mirror 21illuminates an illumination region 26 (refer to FIG. 4(A)) on thereflection surfaces of the plurality of mirror elements 5 in the secondspatial light modulator 25, which is arranged on the irradiated plane ora plane near the irradiated plane, with a uniform illuminationdistribution. The optical members included between the beam expander 11and the condenser optical system 20 forms the illumination opticalsystem ILS. The illumination optical system ILS, the mirror 21, and thespatial light modulator 25 are supported by a frame (not shown).

FIG. 4(A) is a diagram showing the reflection surface of the spatiallight modulator 25 in this embodiment. In FIG. 4(A), the plurality ofsubstantially square mirror elements 5 are arranged so that thereflection surface of the spatial light modulator 25 is elongated in theX direction and arranged at a constant pitch in the X direction and Ydirection to be substantially in close contact with one another. Thatis, the mirror elements 5 are each arranged at a position P (i, j),which is the ith (i=1, 2, . . . ) in the X direction and the jth (j=1,2, . . . ) in the Y direction. As one example, the ratio between thelength of the reflection surface of the spatial light modulator 25 andthe width of the reflection surface (scanning direction of the wafer W)is 4:1, with 1000 mirror elements 5 being arranged in the X direction.The rectangular illumination region 26, which is elongated in the Xdirection, is set to be slightly inward from the profile of thereflection surface of the spatial light modulator 25. The reflectionsurface of the spatial light modulator 25 may be substantially square.

In this embodiment, the mirror elements 5 of the spatial light modulator25 can each be switched between a first angle at which the reflectionsurface of the mirror element 5 is parallel to the XY plane (a state inwhich the drive power is cut in this embodiment) and a second anglerotated by a predetermined angle about the X axis (a state in which thedrive power is supplied in this embodiment). The spatial light modulator25 includes a drive unit 6 for separately controlling the mirrorelements 5 with respect to the angles of the reflection surfaces. Aswill be described later, whenever a predetermined number of pulse lightsare emitted, the main control system 30 provides a modulation controlunit 45, which is shown in FIG. 1, with information on patterns thatshould be exposed onto the wafer. In accordance with the information,the modulation control unit 45 provides the drive unit 6 withinformation on the setting of the reflection surface of each mirrorelement 5. Hereafter, as shown in FIG. 4(B), which is an enlarged viewof portion B in FIG. 4(A), the mirror elements 5 set at the first angleis referred to as mirror elements 5P and the mirror elements 5 set atthe second angle is referred to as mirror elements 5N. In this manner,the mirror elements 5 are only required to be switchable between twoangles. Thus, the spatial light modulator 25 can be enlarged, and eachmirror element 5 can be much smaller than the mirror elements 3 of thefirst spatial light modulator 13. Examples of the structure of thespatial light modulator 25 will be described in detail later.

Returning to FIG. 1, in one example, the projection optical system PLsupported by a column (not shown) is a reduction projection opticalsystem that is non-telecentric toward the spatial light modulator 25(object plane) and telecentric toward the wafer W (image plane). Thatis, in the reflection light IL reflected by each mirror element 5 of thespatial light modulator 25, the projection optical system PL uses theillumination light entering diagonally relative to the Z axis to form apredetermine pattern image on the wafer W, to which resist(photosensitive material) is applied, in an exposure region 27 (regionconjugated with the illumination region 26 of FIG. 4(A)).

In this case, in the spatial light modulator 25, the reflection lightfrom each mirror element 5P, the reflection surface of which is set tothe first angle (state in which the drive power is cut), diagonallyenters the projection optical system PL and becomes an effective imaginglight beam ILP. Reflection beam ILN from each mirror element 5N, thereflection surface of which is set at the second angle, is substantiallyreflected in the −Z direction and does not enter the projection opticalsystem PL. Thus, the reflection beam ILN does not contribute to theformation of an image. The reflection surface angle (second angle) ofthe mirror elements 5N need only be an angle in which the reflectionlight from the mirror elements 5N does not enter the wafer W (an anglethat does not contribute to image formation on the wafer W) and may be,for example, an angle at which the reflection light is shielded by anaperture stop (not shown) in the projection optical system PL. Hence, inthe plurality of mirror elements 5 may be considered as a reflectivemask pattern in which the mirror elements 5P correspond to reflectionunits and the mirror elements 5N correspond to non-reflection units. Inthis embodiment, the switching between the mirror elements 5P and themirror elements 5N may be performed for each pulse light emission of theillumination light IL. Thus, the reflective mask pattern may be variedto any pattern for each pulse light emission using each mirror element 5as a single unit.

By using the projection optical system PL, which is non-telecentrictoward an object, the plane on which the plurality of mirror elements 5of the spatial light modulator 25 are installed is arranged parallel tothe plane on which the wafer W is arranged, that is, the exposuresurface of the wafer W (upper surface of resist) so as to irradiate thewafer W with reflection light from the spatial light modulator 25 viathe projection optical system PL. Further, the reflection light from themirror elements 5P, which are in a state cut off from the drive power,serves as effective imaging light beams. This facilitates control of thespatial light modulator 25.

The projection optical system PL forms a reduced image of a variablepattern (or light intensity distribution substantially corresponding tothe pattern) set by the spatial light modulator 25. For example, whenthe mirror elements 5 have a size of about 20×20 μm, the magnificationof the projection optical system PL may be set to about 1/200 so that avariable pattern having a line width of 100 nm can be projected onto thewafer W. As described above, the mirror elements 5 are only required tobe switched between two angles. This enables further miniaturization.For example, if the mirror elements 5 have a size of several micrometersand the magnification of the projection optical system PL is set toabout 1/50, a variable pattern having a line width of 50 to 100 nm maybe projected onto the wafer W.

In FIG. 1, a wafer holder (not shown) attracts and holds the wafer W onthe wafer stage W. The wafer stage WST performs step movements in the Xdirection and the Y direction on a guide surface (not shown) and movesin the Y direction at a constant velocity. A laser interferometer 33,which measures the position of the wafer stage WST in the X directionand Y direction, the rotation angle of the wafer state WST about the Zaxis, and the like, provides a stage control system 32 with informationon the measurements. Based on control information from the main controlsystem 30 and measurement information from the laser interferometer 33,the stage control system 32 controls the position and velocity of thewafer stage WST with a drive system 34, which includes a linear motor orthe like. To align the wafer W, an alignment system (not shown) or thelike is used to detect the position of an alignment mark on the wafer W.

Next, the structures of the spatial light modulators 13 and 25 shown inFIG. 1 will be discussed.

FIG. 2(A) is an enlarged perspective view showing part of the spatiallight modulator 13 in the illumination optical system ILS of FIG. 1. InFIG. 2(A), the spatial light modulator 13 includes the plurality ofmirror elements 3, which are arranged at a constant pitch in the Xdirection and Z direction in close contact with one another, and thedrive unit 4, which separately controls the plurality of mirror elements3 with respect to the reflection surface angle. For example, severalthousand mirror elements 3 are arranged in the X direction and the Zdirection.

As shown in FIG. 2(B), in one example, the drive mechanism for a mirrorelement 3 includes a hinge member 37 for supporting the mirror element3, four electrodes 35 extending from the hinge member 37, two rodmembers 36 supporting the hinge member 37 on a support substrate 38, andfour electrodes 39 formed on the support substrate 38 facing toward thefour electrodes 35. In this example, the potential difference betweenthe corresponding electrodes 35 and 39 in each of the four sets iscontrolled so as to control the electrostatic force acting between theelectrodes and tilt and incline the hinge member 37. This continuouslycontrols the inclination angle of the reflection surface of the mirrorelement 3, which is supported by the hinge member 37, about twoperpendicular axes within a predetermined variable range. The structureof the spatial light modulator 13 is described in detail in, forexample, Japanese Laid-Open Patent Publication No. 2002-353105.

The mechanism for driving the mirror elements 3 is not limited to thestructure of this embodiment and any other structure may be used.Further, the mirror elements 3 are substantially square planar mirrorsbut may have any shape such as a rectangle. However, from the viewpointof efficient use of light, it is preferable that the mirror elements beshaped to allow for a layout that is free from gaps. Further, it ispreferred that the interval between adjacent mirror elements 3 beminimized. In addition, the mirror elements 3 are shaped to be, forexample, 20×20 μm. However, it is preferred that the mirror elements 3be as small as possible to enable fine adjustments of the illuminationconditions.

Furthermore, a mirror element 3′ having a concave surface as shown inFIG. 2(C) or a mirror element having a convex surface (not shown) may beused as shown in FIG. 2(C).

FIGS. 3(A) and 3(C) each show the reflection light of a plurality ofmirror elements 3A to 3G selected as representatives from a line ofseveral thousand mirror elements 3 arranged in the Z direction of thespatial light modulator 13 of FIG. 1. FIGS. 3(B) and 3(D) show theshapes of secondary light sources (shown by hatching lines) on theillumination pupil plane 22 of FIGS. 3(A) and 3(C).

As shown in FIG. 3(A), the inclination angle about two axes (i.e.,inclination direction and inclination angle) of each of the mirrorelements 3A to 3G in the spatial light modulator 13 is set so that thecorresponding reflection light is converged at two regions that areeccentric from the optical axis AXI on the incident surface of the fly'seye lens 15. As shown in FIG. 3(B), dipolar secondary light sources 23Aand 23B are formed in the Z direction. In this case, the inclinationdirection and inclination angle of the mirror elements in the otherlines of the spatial light modulator 13 are also set so that thereflection light is converged to the corresponding region of either oneof the secondary light sources 23A and 23B and the intensity of thesecondary light sources 23A and 233 are generally uniform (samehereafter). Further, by controlling only the inclination direction andinclination angle of each mirror element 3, the interval between thesecondary light sources 23A and 23B can be controlled as shown byregions B4A and B4B. The Z direction in the illumination pupil plane 22corresponds to the Y direction of the reflection surface of the spatiallight modulator 25 (surface on which the light intensity distributionsubstantially corresponding to transfer pattern is formed).

By setting the inclination direction and inclination angle of eachmirror element 3A to 3G in the spatial light modulator 13 so that thereflection light is converged in a region including the optical axis AXIon the incident surface of the fly's eye lens 15, a circular secondarylight source 24A for normal illumination is formed as shown in FIG.3(D). In this case, by setting only the inclination direction andinclination angle of each mirror element 3, the size (c value) of thesecondary light source 24A can be controlled as shown in region D4.

In the same manner, by separately controlling the mirror elements 3 withrespect to the reflection surface inclination angle about two axes,dipolar secondary light sources 23C and 23D can be formed in the Xdirection as shown in FIG. 3(E), an annular secondary light source 34Bcan be formed as shown in FIG. 3(F), quadrupolar light sources (notshown), and the like can be formed.

The spatial light modulator 25 for the object plane side (mask) of theprojection optical system PL shown in FIG. 1 may have a structure thatis similar to that of the spatial light modulator 13. However, eachmirror element 5 in the spatial light modulator 25 is only required tobe set at the first angle and the second angle as described above. Thus,the drive mechanism of the mirror element 5 may be simpler than thedrive mechanism for the mirror elements 3 of the spatial light modulator13.

Spatial light modulators that can be used as the spatial lightmodulators 13 and 25 are described in, for example, Japanese NationalPhase Laid-Open Patent Publication No. 10-503300 and its correspondingEuropean Patent Publication No. 779530, Japanese Laid-Open PatentPublication No. 2004-78136 and its corresponding U.S. Pat. No.6,900,915, Japanese National Phase Laid-Open Patent Publication No.2006-524349 and its corresponding U.S. Pat. No. 7,095,546, and JapaneseLaid-Open Patent Publication No. 2006-113437. When using these spatiallight modulators in the illumination optical system ILS, the lighttraveling through each reflection surface of the spatial light modulatorenters an intensity distribution formation system (the relay opticalsystem 14) at a predetermined angle and forms a predetermined lightintensity distribution on the illumination pupil plane in accordancewith a control signal sent to the plurality of mirror elements(reflection elements).

Further, as the spatial light modulators 13 and 25, a spatial lightmodulator that is, for example, separately controllable of a pluralityof two-dimensionally arranged mirror elements with respect to thereflection surface heights. Examples of such a spatial light modulatorare described, for example, in Japanese Laid-Open Patent Publication No.6-281869 and its corresponding U.S. Pat. No. 5,312,513, and in FIG. 1dof Japanese National Phase Laid-Open Patent Publication No. 2004-520618and its corresponding U.S. Pat. No. 6,885,493. These spatial lightmodulators form a two-dimensional height distribution and thus affectincident light in the same manner as a phase-type diffraction grating.

The spatial light modulator having a plurality of two-dimensionallyarranged reflection surfaces as described above may be modified inaccordance with the disclosures of, for example, Japanese National PhaseLaid-Open Patent Publication No. 2006-513442 and its corresponding U.S.Pat. No. 6,891,655 or Japanese National Phase Laid-Open PatentPublication No. 2005-524112 and its corresponding U.S. PatentApplication Publication 2005/0095749.

One example of an exposure operation (controlled by the main controlsystem) performed by the exposure apparatus 100 of this embodiment willnow be discussed with reference to the flowchart of FIG. 7. In thiscase, for example, a reduced image of a mask pattern MP, which is shownin FIG. 5(A), is exposed onto the wafer W. Information on the maskpattern MP is stored in a storage of the main control system 30. Themask pattern MP includes line-and-space patterns (hereinafter referredto as the L&S patterns) 40A to 40C arranged at a pitch that is close tothe resolution limit in the X direction, L&S patterns 41A to 41Darranged at a pitch that is close to the resolution limit in the Ydirection, and L&S patterns 42A, 42B, and 43 arranged at a relativelyrough pitch. The L&S patterns 40A to 40C etc. are shown in an enlargedmanner. Further, the mask pattern MP may actually be shaped differentlyfrom the pattern projected onto the wafer W.

The region on the mask pattern MP corresponding to the illuminationregion 26 on the spatial light modulator 25 of FIG. 4(A) defines atransferred region 26M. In this embodiment, the transferred region 26Mis hypothetically moved on the mask pattern M at a constant velocity inthe Y direction in an image memory of the main control system to form alight intensity distribution that corresponds to the pattern that variesin a timed manner in the transferred region 26M, and the wafer W of FIG.1 is moved in synchronism with the movement of the transferred region inthe Y direction, which is the corresponding scanning direction. Further,the hatched portions (L&S pattern 40 etc.) in the mask pattern M? ofFIG. 5(A) are portions where the light intensity is strong. In acorresponding manner, for example, the mirror elements 5P, which areshown by hatched lines, in the spatial light modulator 25 of FIGS. 4(A)and 4(C) show portions where the light intensity is strong (portion atwhich the reflection light travels through the projection optical systemPL).

For example, when exposing the L&S patterns 40A to 40C of FIG. 5(A), theX direction dipolar illumination that uses the secondary light sources23C and 23D of FIG. 3(E) are desirable. When exposing the L&S patterns41A to 41C, the Z direction (Y direction) dipolar illumination that usesthe secondary light sources 23A and 23B of FIG. 3(B) are desirable. Whenexposing the L&S patterns 42A to 43, the normal illumination that usesthe secondary light sources 24A is desirable.

First, in step 121 of FIG. 7, resist is applied to the wafer W. Then, instep 101, the wafer W is loaded onto the wafer stage WST of FIG. 1. Asshown in FIG. 6(A), the surface of the wafer W is divided into shotregions SA onto which a reduced image (referred to as erected image tofacilitate description) of the mask pattern MP of FIG. 5(A) is exposedand which are arranged at a predetermined pitch in the X direction and Ydirection. Next, in step 102, after alignment of the wafer W, to exposeshot regions SA21, SA22, . . . arranged in a single line in the Ydirection on the wafer W of FIG. 6(A), the wafer is positioned at ascanning initiation position. Then, scanning of the transferred region26M in the +Y direction is hypothetically initiated on the mask patternMP of FIG. 5(A), and the scanning of the wafer W in the +Y direction ata constant velocity is synchronously initiated. The arrows in the shotregions SA21 of FIG. 5(A) show the movement direction of the exposureregion 27 relative to the wafer W.

In step 103, the main control system 30 selects as a transfer pattern apattern 28A, which is formed by the L&S patterns 40A to 40C, from thetransferred region 56M of FIG. 5(A). Next, in step 104, the main controlsystem 30 controls the inclination angle of the mirror elements 5 in thespatial light modulator 25 with the modulation control unit 45 and setsthe distribution of the mirror elements 5P and 5N that correspond to thepattern 28A. Then, in step 105, the main control system 30 selectsillumination conditions (here, dipolar illumination in the X direction)that are in accordance with the selected pattern 28A. In step 106, themain control system 30 sets the inclination direction and inclinationangle of each mirror element 3 in the spatial light modulator 13 withthe modulation control unit 31 of FIG. 1 and sets the dipolar secondarylight source shown in FIG. 3(E).

In step 107, the main control system 30 provides the power supplycontrol unit 9 of FIG. 1 with the light emission trigger pulses TP toemit the illumination light IL from the light source 10 for apredetermined number of pulse and exposes the pattern 28A of FIG. 4(A)onto the exposure region 27 of the wafer W. The predetermined number ofpulses may be one or a plural number such as five or ten. Further, thepredetermined number of pulses may be variable. The operations of steps103 to 106 and step 108, which will be described below, are performed athigh speeds, for example, during a single cycle of the pulse lightemissions of the illumination light IL. Thus, the pulse lights of theillumination light IL are emitted in a substantially continuous mannerwhen the wafer W is undergoing scanning exposure.

In step 108, when the mask pattern MP of FIG. 5(A) still includes apattern that has not been transferred, the main control system 30proceeds to step 103, selects a transfer pattern, and repeats theinclination angle setting for the mirror elements 5 in the spatial lightmodulator 25, the selection of the illumination conditions, theinclination direction and inclination angle setting for the mirrorelements 3 in the spatial light modulator 13 in accordance with theselected illumination conditions, and the exposure for a predeterminednumber of pulses (steps 104 to 107). Steps 103 to 107 may be repeated anumber of times on the same pattern (e.g., the L&S pattern 40 a of FIG.5(A)). During such processing, the wafer W undergoes scanning. Thepattern generated by the spatial light modulator 25 of FIG. 1 is thusshifted in the Y direction. Ultimately, the predetermined number ofpulses is adjusted so that the accumulated exposure amount on the waferW for each pattern (e.g., the L&S pattern 40A) in the mask pattern MP ofFIG. 5(A) becomes equal to a predetermined resist sensitivity. In thisprocess, the energy of the pulse light varies between pulses. Therefore,to reduce exposure variations through an averaging effect, the number ofaccumulated pulses for obtaining the resist sensitivity may be greaterthan or equal to a predetermined value.

Further, for example, as shown in FIG. 5(B), when the transferred region26M moves, in addition to the L&S patterns 40A to 40C arranged in the Xdirection, the transferred region 26M also includes the L&S pattern 41Ain the Y direction. In this case, for example, only the L&S patterns 40Ato 40C are selected as a transfer pattern 28B, and the illuminationcondition set accordingly by the spatial light modulator 13 is dipolarillumination in the X direction.

Next, as shown in FIG. 5(C), when the transferred region 26M moves, forexample, only the L&S patterns 41A to 41C arranged in the Y directionare selected as a transfer pattern 28C, and the spatial light modulator25 accordingly sets the distribution of the mirror elements 5P and 5Nthat is in accordance with the pattern 28C as shown in FIG. 4(C).Further, to obtain the illumination condition of dipolar illumination inthe Y direction, the spatial light modulator 13 sets the secondary lightsources 23A and 23B shown in FIG. 3(B).

Subsequently, when the transferred region 26M moves to position 29A asshown by double-dashed line in FIG. 5(A), only the L&S patterns 41B to41D arranged in the Y direction are selected as a transfer pattern 28D.Then, when the transferred region 26M moves to position 29B shown inFIG. 5(B), for example, only the L&S pattern 42A having a rough pitch isselected as a transfer pattern 28E. Further, for example, normalillumination is selected as the illumination condition, and the spatiallight modulator 13 sets the round secondary light source 24A of FIG.3(D). Afterwards, when the transferred region 26M moves by position 29Cshown in FIG. 5(C), only the L&S patterns 42A to 43 having a rough pitchis the transfer pattern. Thus, the illumination condition may continueto be normal illumination.

In step 108, when there are no more non-transferred patterns in the maskpattern MP of FIG. 5(A), the scanning exposure of a single shot regionSA21 is completed. Thus, the operation proceeds to step 109 in which itis determined whether there are still non-exposed regions left on thewafer W. At this point of time, as shown in FIG. 6(A), the shot regionSA22 adjacent to the shot region SA21 on the wafer W has not beenexposed. Thus, the operation returns to step 102. In this case, whilescanning the wafer W in the same direction, as shown in FIG. 5(A), thetransferred region 26M is hypothetically moved to the −Y direction endof the mask pattern MP, and the operation of steps 103 to 108 arerepeated. At the boundary of the shot regions SA21 and SA22 that areadjacent to each other in the scanning direction on the wafer W, thetransferred region 26M is set to the two ends of the mask pattern MP,and the spatial light modulator 25 of FIG. 4(A) forms a pattern bysynthesizing the patterns at positions 29D1 and 29D2 to continuouslyexpose shot regions SA21 to SA22.

In step 109, to further expose a line including shot regions SA31 andSA32 that are adjacent to each other in the X direction on the wafer Was shown in FIG. 6(A), the operation proceeds to step 102 in which thewafer state WST is driven to step-move the wafer W in the X direction.Then, the scanning direction of the wafer for the exposure region atposition 27R is reversed to the −Y direction, the hypothetic movingdirection of the transferred region 26M is set to the −Y direction asviewed in FIG. 5(A), and steps 103 to 108 are repeated.

In step 109, when there are no more unexposed shot regions on the waferW, in step 110, the wafer W undergoes unloading, and exposure isperformed on the next wafer (step 111). Further, in step 122, theexposed wafer undergoes resist development, heating (curing), and acircuit formation process such as etching. The wafer repetitivelyundergoes such exposure and development (lithography) and such processesand then undergoes a device assembly process (processing such as dicing,bonding, and packaging) to manufacture a semiconductor device or thelike.

In this manner, in the exposure apparatus 100 of this embodiment, byusing the spatial light modulator 25, even when there are patterns inthe same transferred region 26M, the patterns actually transferred ontothe wafer W may be grouped and selected in according with the cyclicdirection and miniaturization level, and the illumination conditions maybe optimized by the spatial light modulator 13 in accordance with theselected pattern. Accordingly, the mask pattern MP of FIG. 5(A)including various types of patterns can be exposed with an illuminationcondition that is optimal for each type of pattern. Therefore, theplurality of mirror elements 5 in the spatial light modulator 25 areseparately controlled so that the inclination angle and inclinationdirection are in accordance with the pattern that is to be transferred(or formed) onto the wafer W or pitch and direction of such a pattern.Further, the plurality of mirror elements 3 in the spatial lightmodulator 13 are separately controlled so that the inclination angle andinclination direction are in accordance with the pattern that is to betransferred (or formed) onto the wafer W or pitch and direction of suchpattern or in accordance with the conversion state of the spatial lightmodulator 25. During such control, in this embodiment, the pattern thatis to be transferred is selected in a timed manner. Thus, the transferpattern does not have to be selected, for example, in accordance withthe polarization state of the illumination light, and various types ofpatterns may be included in the mask pattern MP.

This embodiment has the advantages described below.

(1) An exposure method performed by the exposure apparatus 100 of FIG. 1in this embodiment exposes a wafer W (object) with illumination light ILemitted in a plurality of pulse lights. The exposure method includesstep 104 for separately controlling the plurality of mirror elements 5(reflection elements serving as second optical elements) of the spatiallight modulator 25 with respect to the state of the reflection surfaces(and ultimately the conversion state of the spatial light modulator 25),step 106 for controlling the plurality of mirror elements 3 (reflectionelements serving as first optical elements) of the spatial lightmodulator 13 with respect to the state of the reflection state (andultimately the conversion state of the spatial light modulator 13) tocontrol the intensity distribution of the illumination light IL on apredetermined plane, and step 107 for guiding light from the pluralityof mirror elements 3 illuminated by the illumination light IL to theplurality of mirror elements 5 and exposing the wafer W with the lightfrom the plurality of mirror elements 5.

Further, the exposure apparatus 100 of FIG. 1 illuminates an irradiatedplane with illumination light IL emitted in a plurality of pulse lightsand exposes a wafer W with the illumination light IL that travelsthrough the irradiated plane or a plane near the irradiated plane. Theexposure apparatus 100 includes the illumination optical system ILSincluding the spatial light modulator 13 (first optical device), whichincludes the plurality of mirror elements 3 arranged upstream (enteringdirection of the illumination light IL) of the irradiated plane, thespatial light modulator 25 (second optical device) including theplurality of mirror elements 5, and the main control system 30 and themodulation control units 31 and 45 (illumination controller) forcontrolling the conversion state of the spatial light modulator 25 orthe conversion state of the spatial light modulator 13. In thisembodiment, the illumination controller is a device including the maincontrol system 30 and the modulation control units 31 and 45. However,for example, if the modulation control units 31 and 45 share thefunctions of the main control system 30, the illumination controller maybe a device formed by the modulation control units 31 and 45.

The light that enters a wafer W is light contributing to imaging on thewafer W (exposure light), that is, light substantially corresponding toa transfer pattern. Further, light that does not enter the wafer W islight that does not contribute to imaging on the wafer (non-exposurelight). For example, such light may be prevented from entering theprojection optical system PL. Alternatively, such light may be shieldedby an aperture stop (not shown) in the projection optical system PL.

In this embodiment, the plurality of mirror elements 5 are separatelycontrolled with respect to the state of the reflection surfaces. Thisforms a light intensity distribution that is in accordance with pluraltypes of patterns in a timed manner. Further, the plurality of mirrorelements 3 are separately controlled in a timed manner. This optimizesthe distribution of the irradiation angle of the illumination opticalsystem ILS with respect to the mirror elements 5 (illuminationconditions). Accordingly, a mask pattern including plural types ofpattern may be exposed with a high throughput, while optimizing theillumination conditions for each pattern.

(2) In step 104, the main control system 30 and the modulation controlunit 45 control the plurality of mirror elements 5 separately so thatthe state (inclination angle) of the reflection surfaces is inaccordance with the pattern that is to be formed on the wafer W.Further, in step 104, the main control system 30 and the modulationcontrol unit 45 control the plurality of mirror elements 5 separately sothat the state (e.g., inclination angle) is in accordance with the pitchand direction of the patterns that are to be formed on the wafer W.Further, in step 106, the main control system 30 and the modulationcontrol unit 31 control the plurality of mirror elements 3 separately sothat the state (inclination direction and inclination angle) of thereflection surfaces is in accordance with the conversion state of thespatial light modulator 25 or the pattern that is to be formed on thewafer W. Further, in step 106, the main control system 30 and themodulation control unit 31 control the plurality of mirror elements 3separately so that the state (e.g., inclination direction andinclination angle) of the reflection surfaces is in accordance with thepitch and direction of the patterns that are to be formed on the waferW.

In this manner, the illumination conditions are easily optimized inaccordance with the mask pattern (or conversion state of spatial lightmodulator 25) or pattern that is to be formed (exposed) on the wafer W.

Further, exposure may be performed with illumination conditions that areoptimized in accordance with the mask pattern (or conversion state ofthe spatial light modulator 25) or pattern that is to be formed on themask W. This reduces the amount of lost light and enables exposure of asatisfactory pattern.

(3) The predetermined plane is a pupil surface of the illuminationoptical system ILS (illumination pupil plane 22) but may be a plane nearthe pupil plane. Further, the predetermined plane may be a planeconjugated with the illumination pupil plane 22 or a plane near suchconjugated plane.

(4) Further, in the above-described embodiment, whenever theillumination light IL is emitted for a predetermined number of pulses,in steps 104 and 106, the setting of the state of the reflectionsurfaces of the plurality of mirror elements 5 and the setting of thestate of the reflection surfaces of the plurality of mirror elements 3are switched. Accordingly, the switching of patterns that are to beexposed onto the wafer W and the optimization of the illuminationconditions may be performed at high speeds.

Especially, when the predetermined number of pulses is one, theswitching of patterns is performed at the highest speed. As a result,even if the mask pattern MP includes an extremely wide variety ofpatterns, the mask pattern MP can be exposed with a single scanningexposure by optimizing the illumination condition of each pattern.

(5) In other words, in step 104, whenever the illumination light IL isemitted for a predetermined number of pulses, the state of each lightbeam from the plurality of mirror elements 5 in the spatial lightmodulator 25 of FIG. 1 is switched to a first state (e.g., the state ofthe light intensity distribution of the L&S patterns in the X directionof FIG. 4(A)) or a second state (e.g., the state of the light intensitydistribution of the L&S patterns in the Y direction of FIG. 4(C)).

In correspondence, in step 106, whenever the illumination light IL isemitted for a predetermined number of pulses, the state of each lightbeam from the plurality of mirror elements 3 in the spatial lightmodulator 13 is switched to a third state (e.g., the state of dipolarillumination in the X direction of FIG. 3(E)) in correspondence with thefirst state or the state of each light beam from the plurality of mirrorelements 3 in the spatial light modulator 13 is switched to a fourthstate (e.g., the state of dipolar illumination in the Y direction ofFIG. 3(B)) in correspondence with the second state. This optimizes theillumination condition for each pattern.

(6) In step 107, with respect to the plurality of mirror elements 5 inthe spatial light modulator 25, the wafer W is exposed while scanningthe wafer W in a predetermined direction (Y direction, which is thescanning direction) with the wafer stage WST. In step 104, in accordancewith the scanning of the wafer W in the Y direction, the plurality ofmirror elements 5 are separately controlled so that the states of thelight beams are in correspondence with the patterns of the transfersubject that are varied. Thus, even if the mask pattern MP is elongatedin a predetermined manner, the mask pattern MP can be exposed onto thewafer W through a single scanning exposure.

(7) In the exposure apparatus 100 of FIG. 1, the variable pattern (lightintensity distribution) set by the spatial light modulator 25 may beexposed onto the wafer W in accordance with the step and repeattechnique through the projection optical system PL. In this case, thewafer state WST only needs to function to step-move in the X directionand Y direction. Further, as shown in FIG. 6(B), like the shot regionSA21, each shot region SA in the wafer W is divided into a plurality ofshot region portions SB1 to SB5 in correspondence with the size of theexposure region 27 of FIG. 1.

In the exposure region 27, after exposing the shot region SB1 portion inthe shot region SA12, the operation for step-moving the wafer W in the Ydirection with the wafer stage WST and the operation of steps 103 to 107in FIG. 7 are repeated to perform exposure on the other shot regionportions SB2 to SB5. Furthermore, when one of the shot region portionsSB1 to SB5 undergoes exposure, the illumination condition can beoptimized and exposure can be performed for a predetermined number ofpulses so that the accumulated exposure amount reaches the resistsensitivity for each of different types of patterns like the L&S pattern40C arranged in the X direction and the L&S patterns 41A to 41C arrangedin the Y direction in the mask pattern MP of FIG. 5(A).

(8) In the first embodiment, step 104 of FIG. 7 includes, for example,setting the state of the reflection surface of each of the plurality ofmirror elements 5 in the spatial light modulator 25 to either one of astate (first angle) in which the reflection light from the reflectionsurface enters the wafer W and a state (second angle) in which thereflection light does not enter the wafer W. Step 106 includes settingthe state of the reflection surface of each of the plurality of mirrorelements 3 in the spatial light modulator 13 so that the inclinationangle about two axes is within a variable range.

Accordingly, the drive mechanism for the plurality of mirror elements 5can be simplified. Further, the plurality of mirror elements 3 maintainthe usage efficiency of the illumination light IL at a high level andfacilitates the formation of secondary light sources having variousshapes.

The mirror element 3 of the spatial light modulator 13 may be set sothat the reflection surface inclination angle about one surface iswithin a variable range. In such a case, the usage efficiency of theillumination light IL would decrease. However, the light from the mirrorelements 3 used to form a secondary light source may be set so as not toenter the fly's eye lens 15.

(9) Further, in FIG. 1, the plane on which the spatial light modulator25 is arranged (or the plane on which the mirror elements 5 arearranged) is generally parallel to the exposure surface of the wafer W(upper surface of resist). This facilitates the designing andmanufacturing of the exposure apparatus.

(10) In the above-described embodiment, the illumination light IL ispulse lights emitted from an excimer light source but may instead bepulse lights emitted from a solid laser light source. The solid laserlight source increases the pulse frequency to 1 to 2 MHz. Thus, byswitching the state of the reflection surfaces of the mirror elements 5and the mirror elements 3 at high speeds in synchronism with the pulsefrequency, a mask pattern including more types of patterns may beexposed onto a wafer within a short period of time during a singleexposure.

(11) The exposure apparatus 100 includes the light source 10 (lightsource unit), which generates a plurality of pulse lights (illuminationlight). Thus, the emission timing and the like of the pulse lights canbe controlled with high accuracy.

(12) The method for manufacturing a device in the above-describedembodiment includes exposing a wafer W using the exposure method of theabove-described embodiment and processing the exposed wafer W (step122).

The device manufacturing method includes performing lithography with theexposure apparatus 100 of the above-described embodiment. The devicemanufacturing method manufactures a device that includes many types ofcircuit patterns with a high throughput and high accuracy.

The first embodiment may be modified as described below.

(13) In the embodiment of FIG. 1, as the first and second opticaldevices that includes the plurality of first and second opticalelements, the spatial light modulator 25, which includes the pluralityof mirror elements 5 (reflection elements), and the spatial lightmodulator 13, which includes the plurality of mirror elements 3(reflection elements), may be used. However, in lieu of a modulator forat least either one of the spatial light modulator 25 and the spatiallight modulator 13, a liquid crystal cell including a plurality ofpixels (transmissive elements) that control the amount of transmittedlight or a phase device including a plurality of phase elements(variable step elements or the like) that control the phase of thetransmitted light may be used.

(14) Instead of the fly's eye lens 15 of FIG. 1 which is a wavefrontdivision type integrator, a rod type integrator may be used as an innersurface reflective type optical integrator. In this case, as shown inFIG. 1, a converging optical system is additionally arranged toward thespatial light modulator 25 from the relay optical system 14 to form aplane conjugated with the reflection surfaces of the spatial lightmodulator 13, and the rod type integrator is positioned so that itsincident end is located near the conjugated plane.

Further, a relay optical system is used to form on the reflectionsurface of the spatial light modulator an image of an illumination fieldstop, which is arranged on an emission end surface of the rod typeintegrator or near the emission end surface. In this structure, thesecondary light source is formed on a pupil plane of the relay opticalsystem 14 and the converging optical system (a virtual image of asecondary light source is formed near the incident end of the rod typeintegrator). Further, a relay optical system for guiding light from therod type integrator to the spatial light modulator 25 serves as a lightguide optical system.

Second Embodiment

A second embodiment of the present invention will now be discussed withreference to FIG. 8.

FIG. 8 is a schematic diagram showing an exposure apparatus 100A of thisembodiment. In FIG. 8, in which same reference numerals are given tothose components that are the same as the corresponding components ofFIG. 1, a projection optical system PLA, which projects a reduced imageof a variable pattern (light intensity distribution) formed by theplurality of mirror elements 5 in the spatial light modulator 25 ontothe wafer W, is telecentric toward both of the spatial light modulator25 (object plane) and the wafer W (image plane). Thus, the spatial lightmodulator 25 is arranged above the projection optical system PLA so thatits center is substantially aligned with the optical axis of theprojection optical system PLA. Further, the plane on which the mirrorelements 5 in the spatial light modulator 25 are arranged issubstantially parallel to the exposure surface of the wafer W.

In this embodiment, the illumination light IL, which are pulse lightsfrom the illumination optical system ILS, travels via the mirror 21 andthen diagonally upward to enter the plurality of mirror elements 5 inthe spatial light modulator 25. The reflection beam ILN from each mirrorelement 5P, the reflection surface of which is set at a first angleparallel to the XY plane (state in which the drive power is cut off),does not contribute to imaging on the wafer (e.g., does not enter theprojection optical system PLA). The reflection beam ILN from each mirrorelement 5P, the reflection surface of which is set at a first angleparallel to the XY plane (state in which the drive power is cut off),does not contribute to imaging on the wafer (e.g., does not enter theprojection optical system PLA). The reflection light from each mirrorelement 5N, the reflection surface of which is set at a second angle(state in which the drive power is supplied), enters the projectionoptical system PLA and becomes an effective imaging light beam ILP toexpose the wafer W. The remaining structure is the same as the firstembodiment.

In the exposure apparatus 100A of this embodiment, the projectionoptical system, which is telecentric to two sides, may be used. Further,the plane on which the spatial light modulator 25 is arranged (or thesurface on which the mirror elements 5 are arranged) may besubstantially parallel to the exposure surface of the wafer W. Thus, thedesigning and manufacturing of the exposure apparatus is facilitated.

Third Embodiment

A third embodiment of the present invention will now be discussed withreference to FIG. 9.

FIG. 9 schematically shows the structure of an exposure apparatus 100Bin this embodiment. In FIG. 9, in which same reference numerals aregiven to those components that are the same as the correspondingcomponents of FIG. 1, the spatial light modulator 25 is arranged alongthe optical axis AX above a projection optical system PLA, which istelecentric to two sides. The spatial light modulator 25 includes apolarization beam splitter (hereafter, referred to as PBS) 51, a quarterwavelength plate 52, and a plurality of mirror elements 5. Theillumination optical system ILS of this embodiment differs from thefirst embodiment in that the mirror 18 is eliminated from theillumination system ILS and in that the illumination light IL isdirectly emitted in the +Y direction toward the PBS 51. Further, theillumination light IL is linear polarized light of S-polarization(polarization direction is orthogonal to an incident surface on a beamsplitter surface) with respect to the PBS 51.

In this case, the illumination light IL entering the PBS 51 is reflectedupward and converted to circular polarized light by the quarterwavelength plate 52 and then enters the plurality of mirror elements 5in the spatial light modulator 25 substantially orthogonal to thereflection surfaces in a state in which the drive power is cut off. Thereflection beams from the mirror elements 5P, the reflection surfaces ofwhich are set at the first angle (state in which the drive power is cutoff) become effective imaging light beams ILP and enter the quarterwavelength plate 52 along the optical axis AX thereby become P-polarizedlight, which is transmitted through the PBS 51 to enter the projectionoptical system PLA and expose the wafer W. The reflection beams ILN fromthe mirror elements 5N, the reflection surfaces of which are set at thesecond angle (state in which the drive power is cut off), do notcontribute to imaging on the wafer W (for example, does not enter theprojection optical system PL). The remaining structure is the same asthe first embodiment.

In addition to the advantages of the first embodiment, this embodimenthas the advantages described below.

(1) The exposure apparatus 100B of FIG. 9 uses the projection opticalsystem PLA, which is telecentric to two sides. Further, the plane onwhich the spatial light modulator 25 is arranged (or the plane on whichthe mirror elements are arranged) is substantially parallel to theexposure surface of the wafer W. Thus, the designing and manufacturingof the exposure apparatus is facilitated.

(2) Further, in a process corresponding to step 107 of FIG. 7 (processfor irradiating the wafer W with the illumination light IL), theillumination light IL (pulse lights) from the plurality of mirrorelements 3 (refer to FIG. 1) in the spatial light modulator 13 of theillumination optical system ILS of FIG. 9 orthogonally (generallyorthogonal to the reflection surfaces in a state in which the drivepower is cut off) enters the plurality of mirror elements 5 in thespatial light modulator 25. Accordingly, adjustments of the opticalsystems are facilitated.

(3) The PBS 51 (first optical member), which is used so that theillumination light IL orthogonally enters the spatial light modulator25, is arranged between the spatial light modulator 13 in theillumination optical system LS and the spatial light modulator 25.Accordingly, the illumination light IL orthogonally enters the spatiallight modulator 25 with a simple structure. Thus, adjustments of theoptical systems are facilitated, and a projection optical system that istelecentric in two sides may be used. Further, due to the use of thequarter wavelength plate 52 in addition to the PBS 51, there is no lostlight at the PBS 51, and the usage efficiency of the illumination lightIL is high.

The quarter wavelength plate 52 may be eliminated and a normal beamsplitter may be used in lieu of the PBS 51 although this would decreasethe usage efficiency of the illumination light IL.

The present invention may also be applied to an immersion type exposureapparatus described in, for example, PCT Publication No. 99/49504 or aproximity type exposure apparatus that does not include a projectionoptical system.

Further, the present invention is not limited to applications formanufacturing processes of semiconductor devices but may also be widelyapplied to, for example, manufacturing processes for liquid crystaldevices, plasma displays, and the like, and manufacturing processes forvarious types of devices (electronic devices) such as imaging devices(CMOS, CCD, etc.), micro-machines, microelectromechanical systems(MEMS), thin film magnetic heads, and DNA chips. The present inventionmay be embodied in many other specific forms without departing from thespirit or scope of the invention.

What is claimed is:
 1. An exposure apparatus which exposes an objectwith exposure light from a light source, the exposure apparatuscomprising: a first mirror array including a plurality of mirrors andarranged on an optical path of the exposure light from the light source;a first optical system arranged on an optical path of exposure light viathe first mirror array and configured to irradiate an illumination pupilwith the exposure light via the first mirror array, the exposure lighthaving a certain light intensity distribution at the illumination pupil;a second optical system arranged on an optical path of exposure lightvia the first optical system and configured to illuminate an irradiatedplane with the exposure light via the first optical system; a secondmirror array including a plurality of mirrors and arranged on theirradiated plane; a projection optical system including an aperture stopand configured to project a predetermined pattern on the object withexposure light from the second mirror array; and a controller whichcontrols states of the plurality of mirrors of the first and secondmirror arrays, wherein the controller changes the states of theplurality of mirrors of the first mirror array in accordance with thestates of the plurality of mirrors of the second mirror array.
 2. Theexposure apparatus according to claim 1, wherein the controller changesthe states of the plurality of mirrors of the second mirror array inaccordance with the pattern that is to be formed on the object.
 3. Theexposure apparatus according to claim 1, wherein: the exposure light isa pulsed light, and the states of the plurality of mirrors of the secondmirror array are changed whenever a predetermined number of pulsedlights is emitted.
 4. The exposure apparatus according to claim 1,wherein the first optical system includes: a relay optical system havinga front focal point located in a plane on which the plurality of mirrorsof the first mirror array are aligned, and a fly's eye optical systemincluding a plurality of optical surfaces which are two-dimensionallyaligned and are arranged on an optical path of light via the relayoptical system.
 5. The exposure apparatus according to claim 4, whereina rear focal point of the relay optical system is located in a plane onwhich the plurality of optical surfaces of the fly's eye optical systemare aligned.
 6. The exposure apparatus according to claim 1, wherein theillumination pupil is optically conjugated with the aperture stop of theprojection optical system.
 7. An exposure apparatus which exposes anobject with exposure light from a light source, the exposure apparatuscomprising: a first mirror array including a plurality of mirrors andarranged on an optical path of the exposure light from the light source;a first optical system arranged on an optical path of exposure light viathe first mirror array and configured to irradiate an illumination pupilwith the exposure light via the first mirror array, the exposure lighthaving a certain light intensity distribution at the illumination pupil;a second optical system arranged on an optical path of exposure lightvia the first optical system and configured to illuminate an irradiatedplane with the exposure light via the first optical system; a secondmirror array including a plurality of mirrors and arranged on theirradiated plane; a projection optical system including an aperture stopand configured to project a predetermined pattern on the object withexposure light from the second mirror array; and a controller whichcontrols states of the plurality of mirrors of the first and secondmirror arrays, wherein the controller changes the states of theplurality of mirrors of the first mirror array in accordance with thepattern that is to be formed on the object.
 8. The exposure apparatusaccording to claim 7, wherein the controller changes the states of theplurality of mirrors of the second mirror array in accordance with thepattern that is to be formed on the object.
 9. The exposure apparatusaccording to claim 7, wherein: the exposure light is a pulsed light, andthe states of the plurality of mirrors of the second mirror array arechanged whenever a predetermined number of pulsed lights is emitted. 10.The exposure apparatus according to claim 7, wherein the first opticalsystem includes: a relay optical system having a front focal pointlocated in a plane on which the plurality of mirrors of the first mirrorarray are aligned, and a fly's eye optical system including a pluralityof optical surfaces which are two-dimensionally aligned and are arrangedon an optical path of light via the relay optical system.
 11. Theexposure apparatus according to claim 10, wherein a rear focal point ofthe relay optical system is located in a plane on which the plurality ofoptical surfaces of the fly's eye optical system are aligned.
 12. Theexposure apparatus according to claim 7, wherein the illumination pupilis optically conjugated with the aperture stop of the projection opticalsystem.